Preparation And Performance Of Sisal Fibers Reinforced Polymer Based Composites

Sisal fiber?SF?possesses many advantages of low density,low cost,high relative strength,biodegradability and environmental protection.To develop research and application on the high-performance sisal fiber reinforced polymer composites is an inevitable trend to the low carbon environment protection.However,lots of hydrophilic groups exist on the surface of SF,which leads to the bad compatibility between the SF and polymer matrix and limits the composites application.Therefore,carrying out the research on the improvement of interface adhesion to enlarge the range of this kind of composite material has very important significance.In this study,much effort has been made on the surface modification of SF to improve the interface adhesion between SF and the matrix and fabricate the high strength and modulus sisal fiber reinforced composites.On this base,we carried out the research on the Fe₃O₄-RGO treated sisal fiber reinforced polymer based composites in application of electromagnetic shielding application,which could replace the traditional electromagnetic shielding materials partly.There are four parts in our work:?1?We fabricated the sisal fiber reinforced sheet molding compound?SF-SMC?and investigated the effects of SF loading,alkali treatment,KH-550 couple agent treatment and KH-570 couple agent treatment on the mechanical properties,thermal properties and water absorption of the SF-SMC composites.It was found that,the optimal fiber content in the SF-SMC was 10vol%.Compared with the untreated SF-SMC,the tensile?flexural strength and impact strength of the KH-570 treated SF-SMC improved 18.70 %?15.75% and 18.43%,respectively.Furthermore,the temperature of the initial decomposition?IDT?and the maximum weight loss rate?MLT?increased by 30.7°C and 13.2°C,respectively.The water absorption decreased from 1.15 % to 0.45 %.?2?We investigated the effects of SF loading,alkali treatment,GO modification,MAPP coupling agent treatment,the combined GO and MAPP treatment on mechanical properties,thermal properties and crystalline properties of the SF-PP composites.It was found that the optimal fiber content in the SF/PP was 10wt% and the combined GO and MAPP treatmentimproved the properties most effectively.Further more,the improvement of mechanism was also investigated.?3?Fe₃O₄ and Fe₃O₄-RGO were synthesized by a solvothermal method to modify the SF and fabricated the Fe₃O₄-SF/PP and Fe₃O₄-RGO/SF/PP composites.It was found that RGO-Fe₃O₄/SF/PP composite showed higher EMI SE values in comparison to Fe₃O₄/SF/PP composite due to the synergistic effect between RGO and Fe₃O₄ nanoparticles.The RGO-Fe₃O₄/SF/PP composite possessed the maximum EMI SE?%?value of 80.44%,which increase by 143.98% comparing to that of SF/PP composite.Meanwhile,we found that the dominant shielding mechanism of Fe₃O₄/SF/PP and RGO-Fe₃O₄/SF/PP was absorption.